Repulpable and recyclable composite packaging articles and related methods

ABSTRACT

Unexpectedly unique and environmentally friendly composite material structures, storage articles fabricated therefrom, and related methods. The composite structure includes at least one or more fiber-containing layers, such as fiberboard or other layers having fibers from natural and/or synthetic sources, and one or more mineral-containing layers. The mineral-containing layer(s) comprises a thermoplastic bonding agent fixing the mineral particles in place. The fiber-containing layer(s) and mineral-containing layer(s) can be shaped, sized, and manufactured such that the composite structure formed therefrom is capable of being machined to form the storage article. The composite structure can be repulped and recycled without the use of dispersions, emulsions, or aqueous solutions. Further, the composite reduces layer mass requirements for heat seal, barrier, and fiber adhesion compared to polymer layers. The composite structure further has tensile strength and other structural characteristics that allow it to be readily machined into desired storage article forms.

RELATED METHODS

This application is a continuation of U.S. patent application Ser. No.14/211,180, filed Mar. 14, 2014, and claims priority to provisionalapplication Ser. No. 61/879,888, filed on Sep. 19, 2013, and toprovisional application Ser. No. 61/782,291, filed on Mar. 14, 2013.These and all other referenced extrinsic materials are incorporatedherein by reference in their entirety. Where a definition or use of aterm in a reference that is incorporated by reference is inconsistent orcontrary to the definition of that term provided herein, the definitionof that term provided herein is deemed to be controlling.

FIELD OF THE INVENTION

The present embodiments relate generally to repulpable and recyclablecomposite packaging materials and/or finished packaging structures.

BACKGROUND

Packages and packaging materials for retail and shipping purposes aretypically designed to be sufficiently durable to allow reliable use ofthe materials and protection of packaged goods. For environmental andeconomic reasons, pulping and recycling characteristics are criticalconsiderations in the development of such packages and materials. Otherimportant considerations include barrier performance, heat seal duringfabrication, surface energy, and efficiency in manufacturing.

SUMMARY OF THE INVENTION

Compositions and methods that provide for a composite material that isreadily recyclable are provided. The composite material is configured togenerate polymer-containing particles that are readily separable fromfibrous content when subjected to recycling operations.

One embodiment of the inventive concept is a method of recycling acomposite material (e.g. such as a composite material having a caliperof about 0.254 mm to about 0.762 mm), where the method includesobtaining a composite material having a fiber layer and a barrier layerthat is coupled to the fiber layer. This barrier layer includes amineral containing layer having a mineral content of 15% to 70%. Thecomposite material is pulped to produce released fibers and mineralcontaining layer fragments. These mineral containing layer fragmentshave an area of about 0.01 mm² to about 5 mm² and a density ranging fromabout 1.01 g/cm³ to about 4.25 g/cm³. Unwanted materials, which includeat least a portion of the mineral containing layer fragments, areseparated from the released fibers by a screening process having arejection rate of less than 25% by weight of the composite material anda screen cleanliness efficiency is greater than 60%. In some embodimentsthe screening process includes applying a suspension that includes thereleased fibers to one or more screening plates (e.g. a hole screen, aslotted screen, and a contoured screen). Suitable hole screens can haveone or more hole screen openings having a diameter of about 0.8 mm toabout 1.5 mm. Suitable slotted screens can have one or more slottedscreen openings having a width of about 0.1 mm to about 0.4 mm. Suitablecontoured screens can have one or more contoured screen openings havinga width of about 0.1 mm to about 0.4 mm. The pressure drop across suchscreening plates can be less than about 12 kPa of Feed-Accept pressure.

In some embodiments the method includes a post-screening process step,which can include centrifugal cleaning of screen accepts (for example,using a tapered cylinder). Such screen accepts can include at least aportion of the unwanted materials and at least a portion of the releasedfibers. This produces cleaned fibers (e.g. the released fibers separatedfrom the unwanted materials) that are carried inward to an acceptedstock inlet. The unwanted materials include at least a portion of themineral containing layer fragments, and more than 70% by mass of themineral containing layer fragments of the unwanted materials are removedfrom the screen accepts in this process. Such mineral containing layerfragments are at least partially spherical and have a diameter of about0.05 μm to about 150 μm. Overall recovery of the fiber layer of thecomposite is greater than about 70%.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments now will be discussed in detail with an emphasison highlighting the advantageous features. These embodiments depict thenovel and non-obvious repulpable and recyclable composite packagingarticles and related methods shown in the accompanying drawings, whichare for illustrative purposes only. These drawings include the followingfigures, in which like numerals indicate like parts:

FIG. 1 is a schematic side cross-sectional view of a multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 1A is a detail view of the portion of FIG. 1 indicated by thecircle 1A-1A;

FIG. 2 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 3 is a schematic side cross-sectional view of a repulpablemineral-containing material according to the present embodiments;

FIG. 4 is a schematic detail view of a pellet of a mineral-containingresin with mineral particles interspersed within a bonding agentaccording to the present embodiments;

FIG. 5 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments; and

FIG. 6 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 7 is a graph showing the stickies content of Sample 6# from Table12;

FIG. 8 is a graph showing a total ion spectrum of DCM extract from awashout fraction of sample CL WR-2;

FIG. 9 is an envelope formed from a composite material according to thepresent embodiments; and

FIG. 10 is a display tray formed from a composite material according tothe present embodiments.

FIG. 11 is an envelope formed from a composite material according to thepresent embodiments; and

FIG. 12 is a display tray found formed from a composite materialaccording to the present embodiments.

DETAILED DESCRIPTION

The present embodiments relate to methods and compositions providingrepulpable and recyclable consumer packaging for containing, for exampleand without limitation, food products, dry goods, detergents, etc. Moreparticularly, the present embodiments include using mineral-containinglayer(s), minerals bonded by thermoplastic polymers and subsequentlyadhered to fiber-containing layer(s) using extrusion coating, extrusionlamination, or lamination adhering the mineral-containing layercontinuously and substantially to the surface or surfaces of naturalfiber-containing layers such that the finished package can beeffectively repulped and recycled using both pre-consumer andpostconsumer collection methods. The present embodiments providereusable pulp, thus offering reusability and reprocess ability intovaluable recycled paper-containing packaging products. The presentpackaging composites can be used to form one or more layers of all typesof single-layer and multilayer packaging structures, e.g. foldingcartons and the like, including single-wall or multi-wall corrugatedstructures using the composite packaging material as one or more inneror outer liner(s) and/or corrugated medium(s).

It is current practice, for example, to add a film of polyethylene (PE),polypropylene (PP), polyester, wax, or polyvinylidene chloride (PVDC) onpaper substrates to provide a moisture barrier. Also, various types ofemulsion and aqueous coatings are applied to paper substrates for thesame reason. However, it is believed that there are no repulpable andrecyclable solutions that offer the efficiencies of high speedthermoplastic extrusion coating of mineral-containing pellets forming alayer. The present embodiments provide finished composite materialshaving high barrier performance, heat sealability, high performanceadhesion to fiber, strength, repulpability, and low cost of manufacture.Further, other resins may be used to give packaging materials barrierperformance, such as polyacrylates, polyvinyl acetates, and the like.However, these materials are more expensive than wax, polyethylene andPVDC. Predominantly, barrier alternatives are considered by recycling(repulping) mills to be non-repulpable, mainly because they introducequality problems in the fiber recovery process, either by upsetting theprocess, e.g. by plugging filter screens, or by contaminating thefinished product. Approximately 20% of known paperboards are laminatedwith the materials listed above, or similar materials, resulting inproducts that are incompatible within the recycling industry.

A major drawback to polyolefin and other polymer coatings, such as wax,acrylic, polyethylene terephthalate (PET) dispersions, and PVDC barrierlayers, is that they are either difficult to reprocess or recycle andusually discarded, or they can only be processed at a recycling millwith specialized equipment, or, if processible, provide inferior barrierand heat seal performance for packaging articles such as cups or heatsealed folding cartons. For environmental and cost reasons, the disposalof moisture barrier packaging materials has become an important issuefor paper mills and their customers. Repulping these materials posesspecial problems for the industry. The moisture barrier layer manifestsproblems in recovering the useful fiber from the package. Presently,nearly all of these packages are ultimately discarded into landfills orincinerated, which raises issues with respect to the environment andpublic health, particularly for PVDC. Reprocessing packaging to recoverwood fibers is an important source of wood fibers, and helps avoid wasteof high quality and costly fibers.

When forming packaging that contains food products and dry goods, heatscalability is often important for closures. Also, the packagingstructure preferably provides a barrier for moisture, oxygen, oils, andfatty acids. Other desirable characteristics include mechanicalperformance, aesthetics, cosmetics, resistance to chemicals,recyclability, heat sealability, surface energy, ink adhesion, inkwet-ability, film adhesion to fibers, improved surface for glue andadhesive application, and barrier performance (against oxygen, water,moisture, etc.). Therefore, extrusion coating fiber surfaces usingpolymers, (polyolefins being the most common) and bio-polymers is commonpractice.

Two methods are commonly used for reprocessing wood fibers. The firstmethod breaks up the source of wood fibers, such as packaging materials,by repulping, while other materials are filtered out. The second methodbreaks up the packaging materials such that any non-fibrous materialbreaks up into tiny pieces (generally smaller than 1.6 mm), which thenpass through the filter screen(s) with the wood fibers to constitute apulp. This second method is frequently carried out with chemicaladditives and/or additional equipment, making it expensive and thereforeundesirable.

However, no known resins, with our without wax, used in high-performancebarrier layers, can be reprocessed without additional manufacturingsteps. Recycling these materials is therefore difficult if notimpossible. Additionally, the presence of wax in resins frequentlyresults in a lower quantity of usable pulp, and therefore increases theamount of waste. In the repulping process, waste materials may break upinto very tiny particles, often smaller than 0.7 mm. These particlespass through the filter screen(s) and contaminate pulp that is sent tothe paper machine. Problems repulping wax include clogging the felts,gumming up the can dryer causing web breaks, sticky related unacceptablepaper surface cosmetics, and yield reduction.

The repulping of PE and PP barrier layers (as with most polymers) isvery difficult. During reprocessing, while polyolefin is in the pulper,it separates from the fiber and the polyolefin breaks into large pieceswith estimated widths from about 0.3 cm to 3.0 cm, or larger pieces andparticles having densities in a range from about 0.875 g/cm³ to about0.995 g/cm3 and higher. These pieces cause screen plugging, requiringexpensive downtime to clean, and generate solid waste. However,mineralized layers when repulped break down into a preponderance of fromabout 35% to about 99% of much smaller and more dense fragments in sizesof from about 0.0005 mm² to about 2 mm² or larger, having densities fromabout 1.10 g/cm³ to about 4.75 g/cm³. These unique particles provideimproved repulping and recycling processing benefits. Therefore, themineral-containing layers can be applied successfully tofiber-containing layers with improved re-pulpability vs. polymer layerswith mineral-containing layers applied in coat weights in the range offrom about 4 lbs/msf (pounds per thousand square feet) to about 25lbs/msf. The processing of the mineralized layer composite material canbe accomplished using industry standard repulping and recyclingequipment, much of which is further described in this specification.

Also, for normal processing it is important for the recycler to use astandard pulper equipped with a steam line, using typical screens ofvarious sizes and an operating centrifuge. PVDC coating also hasgenerally the same processing issues as PE. Further, other options suchas emulsion and aqueous coating with vinyl content cannot providecomparable barrier performance or high performance heat scalability atlow cost. Also, mixing at the point of manufacture is often required andsingle or multiple layers of vinyl plus separate layers for minerals,for example, may be required. Also, unlike polyolefins, barrier failureis quite common using these types of layers at points of package stressor fracture during converting or subsequent use. Finally, PVDC andrelated coatings provide major environmental toxic hazards and aretherefore a poor option as a barrier layer.

During repulping, non-fibrous barrier layers must be structurallybrittle enough to break into small enough pieces to ensure the fibersefficiently release from the barrier layer and pass through thescreen(s). Also, the pulped barrier layer fragments must not be toosmall to pass through the screen(s) and create process difficulties inthe paper making machine. Finally, the pulped barrier layer piecescannot be so large as to clog the screen(s) and foul the filteringprocess.

By introducing mineral content into a thermoplastic barrier layer usingproper particle specifications and proper amounts of minerals added, themineral-containing polyolefin layer obtains structural attributesproviding for efficient, clean, and proper processing during the pulpingprocess. Also, a 20%-70% mineralized layer easily releases fiber contentthrough the screen(s), resulting in high fiber yields. Further, by usingan extrusion coated thermoplastic, high speed, efficient productionapplying the barrier layer to the fiber can be enjoyed using commonprocesses such as extrusion coating. Without the need for water based orother dispersions, press line applications, emulsions, or use of singleor multiple layers containing vinyl, adjunct or additional layers ofsimilar materials or minerals, the thermoplastic content acts as abonding agent for the particles, bonding the mineral particles together,fixing them in position in a compounded thermoplastic andmineral-containing resin pellet, heated at temperatures above 400° F.,and extrusion coated in-line on a single piece of equipment an extrusionlaminated on a single piece of equipment at high speeds from about 100FPM (feet per minute) up to about 3,500 FPM on paper rolls up to andover from about 30″ to about 140″ wide. The mineral-containing layerresin is extruded as a pre-mixed or master batch pellet, and as such thelayer maintains its original integrity after extrusion. Therefore,unlike aqueous or emulsion coatings, no mixing is required prior tocoating, and drying is not required during production at the point ofprinting and converting. The mineralized polyolefin or polymer layerprovides additional benefits, such as high speed heat sealing andimproved barrier performance. Additional benefits may include anexcellent surface for the application of room temperature and hot meltadhesives when forming a package and high levels of moisture, oil, andfatty acid barrier performance.

The fiber component of the repulpable composite may comprise softwoodfibers, hardwood fibers, or a mixture thereof. For example, the papersubstrate may comprise from about 5% to about 95% (such as from about25% to about 90%) softwood fibers and from about 5% to about 95% (suchas from about 25% to about 90%) hardwood fibers. Paper substrates mayalso have, for example, a basis weight of from about 30 to about 200lbs/3000 sq. ft and a caliper (thickness) of from about 0.006″ to about0.048″.

During paper repulping and processing, the fibers are subjected to acleansing and filtering process provided by one or more screens, thusremoving unwanted materials from the re-pulped fiber. Screen plates arecommonly designed to be either hole, slotted, or contoured screens. Theamount and type of rejected and removed material can have an impact onscreen cleanliness. If the screens become clogged, they fail to functionand must be cleaned, creating expensive downtime during processing. Theplates are normally found one behind another with an A plate having thesmallest perforations, an intermediary B plate, and often a C platehaving the largest perforations. Because of the size and conformation ofplastic coating fragments generated during repulping, the plasticrejects clog and dirty the screening system, creating downtime andgeneral inability to process efficiently. However, mineral-containinglayers create dense particles from about 5 mm² to about 0.01 mm².Therefore, based upon reject rates from about 10% to about 25% by weightof the starting paper, the screen cleanliness efficiency achieved can befrom about 60% to about 100%, including pressure screen devices.Further, the pressure drop, expressed as Feed-Accept pressure, can rangefrom about 2 kPa to about 12 kPa on smooth, contoured, or heavilycontoured screens.

Post screen processing includes centrifugal cleaning of the screenaccepts. This pulp cleaning process uses fluid pressure to createrotational fluid motion in a tapered cylinder, causing denser particlesto move outside faster than lighter particles. During cleaning, goodfiber yields are carried inward and upward to the accepted stock inlet.Impurities such as dirt, metals, inks, sand, and any impurities are heldin the downward current and removed from the bottom of the cleaner.Mineral-containing layer impurities found in fiber accepts and rejectshave a density of from about 1.01 g/cm³ to about 4.25 g/cm³. Because theparticles have large density differences from water, and sizecharacteristics, the particles are effectively removed and cleaned fromthe accepts during cleaning. The mineral-containing impurities processout of the fiber accepts efficiently in High Density, Forward, andThrough Flow cleaners, the cleaners having a diameter of from about 70mm to about 400 mm. Further, these particles process out of fibershaving reject rates on or about 0.1-1% to about 5-30%. Additionally,because some particles are typically somewhat spherical in shape (CwAp)they separate more efficiently during centrifugal cleaning. Finally,because the particles are smaller in size and generally dense, they canoften achieve a removal efficiency of from about 50% to about 95% bymass, particle sizes of from about 150 microns to about 0.05 micronsusing singularly or in combination, specific gravity activatedcentrifugal cleaners, flotation washers, and ultra-dispersion washing,the repulpable and recyclable composite material having a pulperconsistency of from about 3% to about 30%, pulping temperatures of fromabout 100° F. to about 200° F., and pulping times of from about 10minutes to about 60 minutes, with pulping pH from about 6 to about 9.5±0.5. Process pressure screens can have holes from about 0.050″ to about0.075″ with slots from about 0.006″ to about 0.020″.

Table 1, below, illustrates estimated repulpability ranges of acomposite containing paper layer(s) combined with mineralized layer(s).The chart is also applicable when using paper layer(s) fiber finecontent from about 0.5% to 60% by weight of the paper. This data iscongruent using various pulping batch and continuous pulping methodsincluding low consistency continuous, rotor de-trashing, drum pulpinghaving 9-20 RPM, high consistency drum pulping, and drum pulpingcontaining 4 mm to 8 mm holes, pulping consistency from about 3% toabout 20%, also, using disk, pressure, and cylindrical screen types withhole type screen openings from about 0.8 mm to about 1.5 mm and slot andcontoured type openings from about 0.1 mm to about 0.4 mm, furtherincluding coarse to fine screen holes and slots from about 0.150 mm toabout 2.8 mm, and screen rotor circumference speeds from about 10meters/second (m/s) to about 30 m/s.

TABLE 1 Composite Repulpability Mineral Content Thermo- of plasticScreen Total Caliper lbs/3 Barrier Bonding Yield Inorganic Overall (in.)msf Layer(s) Agent (Accepts) Matter Recovery 0.010 136 30%-65% 30%-70%60%-90% 1%-40% 70%-95% 0.012 157 30%-65% 30%-70% 60%-90% 1%-40% 70%-98%0.014 172 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.016 190 30%-65%30%-70% 60%-90% 1%-40% 70%-98% 0.018 208 30%-65% 30%-70% 60%-90% 1%-40%70%-98% 0.020 220 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.022 24130%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.024 259 30%-70% 60%-90% 1%-40%70%-98% 0.026 268 30%-70% 60%-90% 1%-40% 70%-98% 0.028 276 30%-70%60%-90% 1%-40% 70%-98% 0.030 286 30%-70% 60%-90% 1%-40% 70%-98% Note:Percentages are ″by weight″ of the total composition. MSF is ″thousandsquare feet.″ % of inorganic matter is based upon industry standard ashtests. Repulpability data per Tappi and Fibre Box Association industrystandard testing and Georgia Tech IPST reporting.

Various diatomaceous earth mineral fillers and pigments are availablefor use within the repulpable mineral-containing layer within thecomposite structure including mica, silica, clay, kaolin, calciumcarbonate, dolomite, and titanium dioxide to name a few. The fillersoffer improved performance for barrier, opacity, increased stiffness,thermal conductivity, and strength. Fillers are normally less expensivethan polymers and are therefore a very economical component of thepolymer layer. The most commonly used mineral fillers have densities inthe range of 2.4 g/cm³ to 4.9 g/cm³. Most polymers have densities in therange of 0.8 g/cm³ to 1.85 g/cm³ and many can be used as thermoplasticbonding agents.

Filler particles can vary in size and shape. Size can vary from 0.1micron to 10.0 micron mean particle size. An example of very finemineral particles include nano-precipitated calcium carbonate which areless than 100 nanometers in size. Ultrafine nanoparticles can range from0.06 microns to 0.15 microns. These ultrafine particles are useful forcontrolling rheological properties such as viscosity, sag, and slump.Mineral filler particles can have various shapes including e.g. spheres,rods, cubes, blocks, flakes, platelets, and irregular shapes of variousproportions. The relationship between the particles' largest andsmallest dimensions is known as aspect ratio. Together, aspect ratio andshape significantly impact the particles' effect in a composite polymermatrix. In yet other examples, particle hardness relates to coarseness,color to layer cosmetics and opacity. Particle morphology suited for thepresent embodiments are primarily, but not limited to, the cube andblock shapes of salt and calcite having the characteristics shown inTable 2, below. Examples of cubic structures include calcite andfeldspar. Examples of block structures include calcite, feldspar,silica, barite, and nephelite.

TABLE 2 Mineral Physical Properties PARTICLE CLASS CUBE BLOCK TypeCubic, Prismatic, Tabular, Prismatic, Rhombohedral Pinacoid, IrregularAspect/Shape Ratios: Length ~1 1.4-4  Width ~1 1 Thickness ~1  1-<1Sedimentation esd esd Surface Area Equivalence 1.24 1.26-1.5

Mineral particles also often have higher specific gravity than polymers.Therefore, the density increases cost through elevated weight. Manyparticles are surface treated with fatty acids or other organicmaterials, such as stearic acid and other materials to improve polymerdispersion during compounding. Surface treatments also affect dry flowproperties, reduce surface absorption, and alter processingcharacteristics. The specific gravity range potential of the mineralsused in the present embodiments including pigments are from about 1.8 toabout 4.85 g/cm³.

It is advantageous to disperse fillers and pigments (which provideopacity and whiteness to the polymer composite) effectively in order toobtain good performance. For fillers, impact strength, gloss, and otherproperties are improved by good dispersion. For pigments, streakingindicates uneven dispersion, whereas a loss in tinting strength may beobserved if the pigment is not fully de-agglomerated. Agglomerates actas flaws that can initiate crack formation and thus lower impactstrength. In the present embodiments, agglomerates are preferably lessthan about 30 microns to preferably less than about 10 microns in size.

Resin and composite extrudate sensitivity to heat becomes importantduring extrusion coating and extrusion lamination production. Smallalterations during processing have an outsized impact upon pre- andpost-extrusion results. Table 3 is a sample, but not limited to,extrusion coating production ranges for identified mineral-filledresins. In Table 3, the melt index measurements were stated under theguidelines of ASTM method D1238-04, and the density measured under theguidelines of ASTM standard method D1501-03.

TABLE 3 Operating Parameters, Mineralized Composite Resins, Monolayer,Coextrusion and Multilayer Mineral-Containing Composites, toFiber-Containing Layers ROLL Extruder #2-#6 Maximum ranges Coextrusionor Plus & Minus as separate a % of stated Comments below Extruder #1downstream value or stated do not represent Monolayer units valuelimitations RESIN Earth Coating Earth Coating SUPPLIER Standridge ColorStandridge Color GRADE TBD TBD NUMBER MELT FLOW - EST: EST: 4 g 10/minto Interspersed and Carrier 16 g/10 min 16 g/10 min 16 g/10 minnon-interspersed Resin(s)/bonding agent COMPOUND 1.25 g/cm³ 1.25 g/cm³1.01-4.90 g/cm³ Molecular DENSITY weight from (Mz 150,00 to 300,000)MINERAL 40% 40% General mineral Interspersed and CONTENT content 15-60%non-interspersed by weight MELT 590° F. (307° C.) TBD ±20% TEMPERATUREDESIRED 1600-2200 psi TBD 1200-2500 psi From 1 to 6 BARREL extrudersPRESS. Composite Melt 2-12 g/10 min 2-12 g/10 min 2 g/10 min-14 g/Interspersed and Flow 10 min non-interspersed Air Gap 8″ 4″-12″ 4″-16″Die Gap 0.025″-0.030″ 0.025″-0.040″ 0.020″-0.050″ From 1 to 6Coextrusion Monolayer and Initial Settings Maximum Settings Die MaximumCoextrusion or Barrel Zones Adjustment Zone Adjustment Die separateBarrel Zones Zone downstream #2-#6 Co-layers TEMPERATURE SETTINGS MeltTemperature 590° F. Up to ±25% BARREL ZONE 405° F. Up to ±35% Die Zone 1585° F. ±25% #1 BARREL ZONE 540° F. Up to ±35% Die Zones 2-10 595° F.±25% #2 (as applicable to equipment) BARREL ZONE 575° F. Up to ±35% DieZone 11 (as 585° F. ±25% #3 applicable to equipment) BARREL ZONE 590° F.Up to ±35% #4 BARREL ZONE 590° F. Up to ±35% #5 Other barrel 590° F. Upto ±35% Other die zones Up to ±35% Zones, if if applicable applicable onspecific equipment

Molecular chains in crystalline areas are arranged somewhat parallel toeach other. In amorphous areas they are random. This mixture ofcrystalline and amorphous regions is essential to the extrusion of goodextrusion coatings. The crystals can act as a filler in the matrix, andso can mineralization, improving some mechanical properties. A totallyamorphous polyolefin would be grease-like and have poor physicalproperties. A totally crystalline polymer would be very hard andbrittle. High-density polyethylene (HDPE) resins have molecular chainswith comparatively few side chain branches. Therefore, the chains arepacked closely together. Polyethylene, polypropylene, and polyesters aresemi-crystalline. The result is crystallinity up to 95%. Low-densitypolyethylene (LDPE) resins have, generally, a crystallinity ranging from60% to 75%, and linear low-density polyethylene (LLDPE) resins havecrystallinity from 60% to 85%. Density ranges for extrusion coatingresins include LDPE resins that range from 0.915 g/cm³ to 0.925 g/cm³,LLDPE resins have densities ranging from 0.910 g/cm³ to 0.940 g/cm³, andmedium-density polyethylene (MDPE) resins have densities ranging from0.926 g/cm3 to 0.940 g/cm³. HDPE resins range from 0.941 g/cm³ to 0.955g/cm³. The density of PP resins range from 0.890 g/cm³ to 0.915 g/cm³.

Addition of a mineral filler to the polymer results in a rise inviscosity. The addition of filler may also change the amount ofcrystallinity in the polymer. As polymer crystals are impermeable to lowmolecular weight species, an increase in crystallinity also results inimproved barrier properties, through increased tortuosity. This effectis expected to be prevalent for fillers that induce a high degree oftranscrystallinity. Some minerals can change the crystallizationbehavior of some thermoplastics and thus the properties of the polymerphase are not those of virgin material, providing novel characteristicsduring processing and in the performance of the finished compositestructure. Thermoplastics crystallize in the cooling phase and solidify.Solidification for semi-crystalline polymers is largely due to theformation of crystals, creating stiffer regions surrounding theamorphous area of the polymer matrix. When used correctly, mineralfillers can act as nucleating agents, normally at higher temperatures.This process can provide mechanical properties in the polymer compositefavorable to high barrier performance and adhesion to fiber surfaceswithout a detrimental effect on heat sealing characteristics. Mineralscan begin to significantly affect crystallinity when used from about 15%to about 70% by weight of the polymer composite. Some of the factorsinfluencing mechanical adhesion to paper include extrudate temperature,oxidation, and penetration into the fibers. Mineral onset temperaturesof the polymer extrudate influence cooling rate upon die exit to the niproller, which can be adjusted by the extruder air gap setting. Other keyfactors include the mass of the polymers of the polymer interface layer.The crystalline onset temperatures vary, however, examples are shown inTable 4, below.

TABLE 4 Selected Polymers with Estimated Mineral Onset TemperaturesUnfilled Polypropylene 120-122° C. Calcium Carbonate 120-125° C.Dolomite 120-131° C. Talc 120-134° C. Silica 120-122° C. Mineral Fiber120-122° C. Mica 120-124

Further, homogeneous blends of solid olefin polymers with varyingdensities and melt indexes can be mixed within the mineral compositelayer, either interspersed or noninterspersed through coextrusion. Themineral-containing composite layer can be applied and bondedsubstantially and continuously on at least a fiber-containing layerusing extrusion or extrusion lamination, including blown film, cast, orextrusion coating methods. Polymer content of the mineral-containinglayer can be used as a tie layer for interspersed and non-interspersedconstructions as well as particle bonding agents within each individuallayer. These bonding agents or tie layers can include individually, orin mixtures, polymers of monoolefins and diolefins, e.g. polypropylene,polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene,polyvinylcyclohexane, polyisoprene or polybutadiene, homogeneousmettallocene copolymers, and polymers of cycloolefins, e.g. cyclopenteneor norbornene, polyethylene, cross-linked polyethylene, ethylene oxideand high density polyethylene, medium molecular weight high densitypolyethylene, ultra heavy weight high density polyethylene, low densitypolyethylene, very low density polyethylene, ultra low densitypolyethylene; copolymers of monoloefins and diolefins with one anotheror with other vinyl monomers, e.g. ethylene/propylene copolymers, linearlow density polyethylene, and blends thereof with low densitypolyethylene, propylene but-1-ene, copolymers ethylene,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/octene copolymers,ethylene/methylepentene copolymers, ethylene/octene copolymers,ethylene/vinyelcyclohexane copolymers, ethylene/cycloolefin copolymers,COC, ethylene/I-olefin copolymers, the 1-olefin being produced in situ;propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/vinylcyclohexene copolymers, ethylene vinyl acetate copolymers,ethylene/alkyl methacrylate copolymers, ethylene/acrylic acid copolymersor ethylene/acrylic acid copolymers and salts thereof (ionomers) andterapolymers of ethylene with propylene and diene, such as, for example,hexadiene, dicyclopentadiene or ethylidenenorbornene; homopolymers andcopolymers that may have any desired three dimensional structure(stereo-structure), such as, for example, syndiotactic, isotactic,hemiisotactic or atactic stereoblock polymers are also possible;polystyrene, poly methylstyrene, poly alpha-methylstyrene, aromatichomopolymers and copolymers derived from vinylaromatic monomers,including styrene, alpha-methylstyrene, all isomers of vinyl toluene, inparticular p-vinyltoluene, all isomers of ethylstyrene, propylstyrene,vinylbiphenyl, vinylnaphthalene and blends thereof, homopolymers andcopolymers of may have any desired three dimensional structure,including syndiotactic, isotactic, hemiisotactic or atactic, stereoblockpolymers; copolymer, including the above mentioned vinylaromaticmonomers and commoners selected from ethylene, propylene, dienes,nitriles, acids, maleic anhydrides, vinyl acetates and vinyl chloridesor acryloyl derivatives and mixtures thereof˜ for examplestyrene/butadiene, styrene/acrylonitrile, styrene/ethylene(interpolymers) styrene/alkymethacrylate, styrene/butadiene/alkylacrylate, styrene/butadiene/alkyl methacrylate, styrene/maleicanhydride, styrene copolymers; hydrogen saturated aromatic polymersderived from by saturation of said polymers, includingpolycyclohexylethylene; polymers derived from alpha, beta-unsaturatedacids and derivatives; unsaturated monomers such asacrylonitrile/butadiene copolymers acrylate copolymers, halidecopolymers and amines from acyl derivatives or acetals; copolymers witholefins, homopolymers and copolymers of cyclic ethers; polyamides andcopolyamides derived from diamines and dicarboxylic acids and or fromaminocarboxylic acids and corresponding lactams; polyesters andpolyesters derived from dicarboxylic acids and dials and fromhydroxycarboxylic acids or the corresponding lactones; blockedcopolyetheresters derived from hydroxyl terminated polyethers;polyketones, polysulfones, polyethersulfones, and polyetherketones;cross-linked polymers derived from aldehydes on the one hand phenols,ureas, and melamines such as phenol/formaldehyde resins and cross-linkedacrylic resins derived from substantial acrylates, e.g. epoxyacrylates,urethaneacrylates or polyesteracrylates and starch; polymers andcopolymers of such materials as polybutylene succinate, polymers andcopolymers of N-vinylpyrroolidone such as polyvinylpyrrolidone, andcrosslinked polyvinylpyrrolidone, ethyl vinyl alcohol. More examples ofthermoplastic polymers suitable for the mineral-containing compositeinclude polypropylene, high density polyethylene combined with MS0825Nanoreinforced POSS polypropylene, thermoplastic elastomers,thermoplastic vulcinates, polyvinylchloride, polylactic acid, virgin andrecycled polyesters, cellulosics, polyamides, polycarbonate,polybutylene tereaphthylate, polyester elastomers, thermoplasticpolyurethane, cyclic olefin copolymer; biodegradable polymers such asCereplast-Polylactic acid, Purac-Lactide PLA, Nee Corp PLA, MitsubishiChemical Corp GS PLS resins, Natureworks LLC PLA,Cereplast-Biopropropylene, Spartech PLA Rejuven 8, resins made fromstarch, cellulose, polyhydroxy alcanoates, polycaprolactone,polybutylene succinate or combinations thereof, such as Ecoflex FBX 7011and Ecovio L Resins from BASF, polyvinylchloride and recycled andreclaimed polyester such as Nodax biodegradable polyester by P & G.

The mineral-containing layer can include coupling agents from about0.05% to about 15% of the weight of the mineral-containing layer. Theagents aid in the mixing and the filling of the mineral into the polymermatrix. Functional coupling groups include (Pyro-) phosphato, Benzenesulfonyl and ethylene diamino. These can be added to thermoplasticsincluding polyethylene, polypropylene, polyester, and ethyl vinylalcohol, aluminate, siloxane, silane, anlino, malice anhydride, vinyland methacryl. The results of these combinations improve adhesion tofibers, heat seal strength, heat seal activation temperatures, surfaceenergy, opacity, and cosmetics. Mineral content can include, but is notlimited to, wollanstonite, hydrated and non-hydrated, magnesiumsilicate, barium sulfate, barium ferrite, magnesium hydroxide, magnesiumcarbonate, aluminum trihydroxide, magnesium carbonate, aluminumtrihydroxide, natural silica or sand, cristobalite, diaonite,novaculite, quartz tripoli clay calcined, muscovite, nepheliner-syenite,feldspar, calcium sulfate-gypsum, terra alba, selenite, cristobalite,domite, silton mica, hydratized aluminum silicates, coke,montmorillonite (MMT), attapulgite (AT) carbon black, pecan nut flour,cellulose particles, wood flour, fly ash, starch, TiO₂ and otherpigments, barium carbonate, terra alba, selenite, nepheline-syenite,muscavite, pectolite, chrysotile, borates, sulfacates, nano-particles ofthe above from 0.01 to 0.25 micron particle size, and precipitated andground calcium carbonate. Among, but not limited procedures generallyinvolving the use of polymerization initiators of catalysts for thepolymerization of butene-I monomer to polymers of high molecular weight,preferably catalytic systems used in such procedures are the reactionproducts of metal alkyl compounds such as aluminum triethyl, and a heavymetal compound, such as the trihalides of Groups IV-VI metals of theperiodic table, e.g. titanium, vanadium, chromium, zirconium, molybdenumand tungsten. The formation of polymers exhibiting substantial isotacticproperties as wells as the variations in the molecular weight and thenature of the polymerization catalyst, co-reactants, and reactionconditions. Suitable, but not limited to, isotatic polybutylenes arerelatively rigid at normal temperatures but flow readily when heated,and they most preferably, should show good flow when heated, expressedin melt:flow. Applicable isotatic polybutylenes should show a melt flowof from 0.1 to 500, preferably 0.2 to 300, more preferably from 0.4 to40, most preferably 1 to 4. Other polymers expressed within the contentsof the present specification should also be considered within theseparameters.

Regarding the mineral-containing composite layer, upon substantially andcontinuously bonding to the fiber-containing using extrusion coating orextrusion lamination techniques, the layer of which can then be used toform a laminated structure of which the mineral-containing layer can beused as a peel coat onto a desired backing material. The best peel seal,for example, to the mineral-containing layer of the composite, may beselected from poly-4-methyl pentene, nylon, high-density polyethylene(HDPE), aluminum foil, polycarbonate polystyrene, polyurethane,polyvinyl chloride, polyester, polyacrylonitrile, polypropylene (PP),and paper. An example extrusion process can be accomplished with a screwor pneumatic tube. Sometimes the mineralized polymers can be combinedwith such materials as plasticizers lubricants, stabilizers, andcolorants by means of Banbury mixers. The resulting mix is then extrudedthrough rod shaped dies and chipped into pellets. Pelletized mineralizedpolymer can then enhance the mineral and other content by “letting down”the resin pellet mix with inline or offline mixing capability beforebeing fed into the end of a, for example, screw-type extruder, heated,and mixed into a viscous fluid or semi-fluid in the extruder barrel forfurther processing to the die. Further, when properly dispersed theinteraction between the mineral particles and the polymer contentwithout covalent bonding, results in improved van der Waals forces thatprovide attraction between the materials. This interaction results insome adhesion in the composite during extrusion, resulting in anabsorbed polymer layer on the filler surface. These considerationscombined with the unique attributes of the mineral content dispersedwithin the polymeric matrix of both monolayer and multilayer mineralcomposite layers impact the application of heat that initiates themelting of semi-crystalline polymers, causing the polymer molecules tobetter diffuse across the interface. Given sufficient time, the diffusedpolymers form entanglements at the inter-facial layer. This effect ispossible at extrusion line speeds from up to about 100 FPM and extrusionlamination up to about 3,500 FPM, using semi-crystalline mineralizedresin blends with extrusion equipment die and barrel zone temperaturesfrom about 540 degrees to about 615 degrees F. Because of improvedmineral thermal properties, oxidation of the extrudate upon exiting thedie but before fiber contact improves from about 10-50%, thus greatlystrengthening fiber bonding characteristics under normal equipmentoperating conditions.

Molecular weight ranges of the polymer bonding agent component of themineral containing layer are from about Mw 10,000 to about Mw 100,000.Further, about 10%-70% of the polymer bonding agent may have a branchingindex (g′) of about 0.99 or less as measured at the Z-average molecularweight (Mz) of the polymer. Some, part, or all of the mineral containinglayer polymer bonding agent is preferred but not required to have anisotactic run length of from about 1 to about 40. Further, the polymerbonding agent of the mineral containing layer has a shear rate range offrom about 1 to about 10,000 at temperatures from about 180° C. to about410° C.

TABLE 5 Particle characteristics of CaCO₃ Fatty Acids Particle CoatingIncluding Stearates Hunter Reflectance (Green)  91-97% HunterReflectance (Blue)  89-96% Mohs Hardness 2.75-4.0  pH in Water, 5%Slurry, 23° C. 8.5-10.5 Resistance in Water, ohms, 23° C. 5,000-25,000ASTM D1119 Max % on 325 Mesh 0.05-0.5  Volume Resistivity @ 25° C.10⁹-10¹¹ ohms pH 8.5-10.5 Standard Heat of Formation, CaCO₃ from its288.45-288.49 Kg-cal/mole Elements 25° C. Standard Free Energy ofFormation, CaCO₃ 269.53-269.78 Kg-cal/mole from its Elements 25° C.Specific Heat (between 0 to 100° C.) 0.200-0.214  Heat Conductivity0.00071 g · ca/ sec · cm² · 1 cm thick @ 25° C. Coefficient of LinearExpansion C = 9 × 10⁻⁶ @ 25 to 100° C. C = 11.7 × 10 @ 25 to 100° C.

Also, nano-cellulose can be used in the mineral-containing compositelayer having a crystalline content from about 40%-70%, includingnano-fibrils, micro-fibrils, and nanofibril bundles, having lateraldimensions from about 0.4-30 nanometers (nm) to several microns, andhighly crystalline nano-whiskers from about 100 to 1000 nanometers.Nanocellulose fiber widths are from about 3-5 nm and from about 5-15 nm,having charge densities from about 0.5 meq/g to about 1.5 meq/g, withthe nano-cellulose having a stiffness from about an order of 140-220 GPaand tensile strength from about 400-600 MPa.

The mineral-containing interspersed or non-interspersed polymercomposite layer can be substantially and continuously directly bonded toa fiber surface or to the fiber surface interface adhesive layer usingextrusion coating or extrusion lamination. Further, the fiber containinglayer can contain inorganic mineral coatings and fillers, e.g. clay,kaolin, CaC03, mica, silica, TiO₂ and other pigments, etc. Othermaterials found in the fiber-containing layer include vinyl andpolymeric fillers and surface treatments such as starch and latex.Preferred characteristics of the fiber-containing layer bound to themineral-containing layer include, but are not limited to, a smoothnessrange of about 150 to about 200 Bekk seconds, and an ash content fromabout 1% to about 40% by weight. Also, in this example, thefiber-containing layer coefficient of static friction, μ, is from about0.02 to about 0.50. Identified cellulose within the fiber-containinglayer preferably has a thermal conductivity from about 0.034 to about0.05 W/m·K. If using air-laid paper or non-woven fibers, the fibercontent is preferably from about 40% to about 65% of the layer byweight. Other preferred, but not limiting, characteristics of thefiber-containing layer are shown in Table 6, below.

TABLE 6 Fiber Layer Characteristics Fiber Aspect Ratio (Average)  5-100Fiber Thickness (Softwood) 1.5-30 mm Fiber Thickness (Hardwood) 0.5-30mm Filled Fiber Content 1% to 30% Fiber Density 0.3-0.7 g/cm2 FiberDiameter 16-42 microns Fiber Coarseness 16-42 mg/100 m Fiber Pulp TypesMechanical, Thermo-Mechanical, Chemi- (Single- to Triple-Layered)Thermo-Mechanical, and Chemical Permeability 0.11-110 m² × 10¹⁵ HydrogenIon Concentration 4.5-10   Tear Strength (Tappi 496, 56-250 402) TearResistance (Tappi 414) M49-250 Moisture Content 2%-18% by Weight

Coextrusion methods provide the possibility for non-interspersed contactlayers within the mineral-containing layer. Based on performance andstructural requirements, the finished composite structures can containseparate layers in the composite that can vary based on types of mineraland amount of mineral content per layer, degrees of amorphous andcrystalline content per layer, and type of polymer resin and resin mixesper layer. The more extruders feeding a common die assembly, the morelayered options become available to the noninterspersedmineral-containing layer. The number of extruders depends on the numberof different materials comprising the coextruded film. For example, anon-interspersed mineral containing composite may comprise a three-layerto six-layer coextrusion including a barrier material core that couldbe, for example, a high density polyethylene and low densitypolyethylene mix having a 25% to 65% mineral content by weight in thefirst base layer, this layer making contact with the fiber surface.Subsequent layers may contain differing mineral contents, neat LDPE, orpolypropylene. Another example is a six-layer coextrusion including abottom layer of LDPE, a tie-layer resin, a 20% to 65% mineral-containingpolypropylene barrier resin, a tie-layer, and an EVA copolymer layer,and a final layer of polyester. Any mineral containing barrier layeraccording to the present embodiments may have a basis weight from about4 lbs/3 msf to about 60 lbs/3 msf, a density from about 1.10 g/cm³ toabout 1.75 g/cm³, and/or a caliper from about 0.30 mil to about 3 mil.Tie-layers often are used in the coextrusion coating of multiple layerconstructions where mineral-containing polymers or other resins wouldnot bond otherwise, and tie-layers are applied between layers of thesematerials to enable desired adhesion. Another example multilayer filmconstruction is 25%-65% mineral content LLDPE/tie-layer/EVOHbarrier/tie-layer/EVA. Interspersed, e.g. monolayer, andnoninterspersed, e.g. multilayer, coextrusions can comprise from one tosix layers of the mineral containing layer substantially andcontinuously bonded across the surface of a fiber-containing layer.Layers can be designed to improve hot tack, heat-sealability, sealactivation temperature, and extrudate adhesion to fiber, mineralenhancement of barrier performance, surface energy, hot and cold glueadhesion improvements, etc.

Table 7, below, shows example layer constructions (not limited to) foundin the mineral-containing resin and extrusion coated or laminatecomposite structure. The preferred single layer ranges contain fromabout 0% to about 65% by weight mineral content, from 25%-80% amorphousto 25%-80% crystalline structure by weight, and 25%-65% cellulose,nanocellulose, or nano-minerals by weight. Also, the mineral content ofthe mineral-containing layer(s) may comprise different fillers withdifferent densities, size, and shape depending upon the desired outcomeof the final composite structure.

TABLE 7 Examples of Non-Interspersed (Multilayered) Mineral CompositeLayers Layer Example Example Example Example Example Example Structure 12 3 4 5 6 Monolayer LDPE HDPE LDPE-HDPE LDPE-MMW LLDPE- PLA-bio (1)resin blend HDPE resin LDPE resin derived blend blend starch based resinblend Monolayer Bio- LDPE-bio LDPE-LLDPE-bio LDPE-HDPE- PP-bio ULDPE-(2) derived, derived derived starch LLDPE blend derived starch HDPE-starch starch blend based bio polymer polymer polymer derived blendblend blend starch polymer blend 3-layer HDPE- HDPE-PP HDPE-PET LDPE-PPLLDPE-PET EVA-LDPE LDPE 4-layer EVA- HDPE- Biaxially oriented OrientedEVA-PE- PVC- ethylene EVA- homopolypropylene- polypropylene- MMWHDPE-ABS-PC vinyl Ionomer polyester- HDPE-PE- oriented Nylon acetate resin-polypropylene-PE metallized polypropylene EEA- Polyamides- PET ethyleneacrylic acid- HDPE- EAA ethylene acrylic acid

Additionally, if relative clarity is desired in the mineral-containingcomposite layer the following resins are possible, but not limiting,bonding agents for these materials: carboxy-polymethyelene, polyacrylicacid polymers and copolymers, hydroxypropylcellulose, cellulose ethers,salts for poly(methyl vinyl ether-co-maleic anhydride), amorphous nylon,polyvinylchloride, polymethylpentene, methylmethacrylate-acrylonitrile-butadiene-styrene, acrylonitrile-styrene,poly carbonate, polystyrene, poly methylacrylate, polyvinyl pyrrolidone,poly (vinylpyrrolidone-co-vinyl acetate), polyesters, parylene,polyethylene naphatalate, ethylene vinyl alcohol, and poly lactic acidscontaining from about 10% to about 65% mineral content. Variousmineral-containing layer polymer and mineral content can be determinedbased upon performance and content requirements considering theparameters shown in Table 7, above. Branched, highly branched, andlinear polymer combinations are possible in all composite layerconstructions. Examples are shown in Table 7 (not limited tocombinations within the table) of the interspersed and non-interspersedmineral-containing layer constructions, not including tie layers. Layercombinations depend on coextrusion die design, flow properties, andprocessing temperature, allowing for coextrusion fusion layers and/orsubsequently extrusion laminating or laminating the layers into thefinal mineral-containing composition, of which individual(noninterspersed) or total combination of layers have by weight mineralcontent of about 20%-65%. Layers can be uniaxially or biaxially oriented(including stretching) from about 1.2 times to about 7 times in themachine direction (MD) and from about 5 times to about 10 times in thecross-machine (transverse) direction (CD), and stretched from about 10%to about 75% in both the MD and CD directions. Generally, althoughwithout limitation, polyolefin mineral content bonding agents havenumber average molecular weight distributions (Mn) of from about 5,500to about 13,000, weight average molecular weight (Mw) of from about170,000 to about 490,000, and Z average molecular weight (Mz) of fromabout 170,000 to about 450,000. A coextruded mineral-containing layermay differ in molecular weight, density, melt index, and/orpolydispersity index within the finished layer structure. Thepolydispersity index is the weight average molecular weight (Mw) dividedby the number average molecular weight (Mn). For example only, andwithout limitation, the mineral-containing layer may have a Mw/Mn ratioof from about 6.50 to about 9.50. Using wet or dry ground CaCO₃ as anexample, it can be surface treated at levels from about 1.6 to about 3.5mg surface agent/m² of CaCO₃. The surface treatment can be appliedbefore, during, or after grinding. Mean particle sizes range from,without limitation, about 0.7 microns to about 2.5 microns, having a topcut from about d98 of 4-15 microns, and a surface area of from about 3.3m²/g to about 10.0 m²/g. For improved dispersion into the polyolefinbonding agent, the CaCO₃ mineral content can be coated with fatty acidsfrom between, without limitation, about 8 to about 24 carbon atoms.

The preferred surface treatment range is about 0.6% to about 1.5% byweight of treatment agent or about 90%-99% by weight of CaCO₃.Polyolefin bonding agents having lower molecular weights and high meltindex provide improved downstream moisture barrier characteristics.Preferred mineral layer content could include finely divided wet groundmarble with 65% solids in the presence of a sodium polyacrylatedispersant, dried, and surface treated, and also dispersant at 20%solids, dried, and surface treated.

Testing methods for measuring moisture vapor transmission rates andwater vapor transmission rates (MVTR/WVTR) often involve tropicalconditions (100° F. and 90% RH) according to TAPPI Test Method T-464,orienting the barrier coating toward the higher humidity of the chamberatmosphere, when it is present on the surface. For water resistance, thestandard short (2 minute) and long (20 minute) Cobb test is often used.For oil, two tests are commonly used. The first is the 3M kit test perTAPPI T-559 standards, coating film weight as measured by TAPPI 410standards. The second is red dyed canola oil and castor oil exposure tothe coating surface using a 2-minute and a 20-minute Cobb ring.

Extruded mineral-containing interspersed and non-interspersed compositelayers of the present embodiments demonstrate high barrier performancecharacteristics when substantially and continuously bonded tofiber-containing layers. The fiber-containing layers may include intheir composition or surface, but are not limited to, mineral andpolymeric sizings, surface treatments, coatings, and mineral fillers.Some advantages of the non-fiber content of the fiber-containing layerinclude improved fiber layer printability, ink hold out, dynamic waterabsorption, water resistance, sheet gloss, whiteness, delta gloss, pickstrength, and surface smoothness. Often, mineral content containedwithin or upon one or more opposing surfaces of the fiber-containinglayer can include, but is not limited to, clay, calcined clay, orcombinations thereof. The minerals are frequently applied to the surfaceof the fiber-containing layer through a blade or air coating process.Common mineral binding methods include the use of protein systems suchas a mixture of vinyl acrylic/protein co-binders. Another non-limitingexample is tri-binder systems, e.g. SB/Pvac/Protein. Further, pigmentssuch as TiO₂ can be included to improve whiteness characteristics. Thenature of the fiber layer's mineral and binder content can impact theselection of the non-interspersed and interspersed mineral-containinglayer characteristics when bonded substantially and continuously to oneor more sides of the fiber-containing layer(s), which comprise part ofthe composite structure. Examples of non-fiber content in thefiber-containing layer include, but are not limited to, 50%-95% of #1clay or #1 fine clay, 3%-20% by part calcined clay, 3%-40% by part Ti02,2%-45% vinyl acrylic, and from about 1% to about 35% protein binders,co-binders, or tri-binders.

Also, the fiber-containing layer surfaces can have from about 55% toabout 88% TAPPI 452 surface brightness. The examples shown in Table 8,below, illustrate acceptable, but not limiting, fiber-containing layercharacteristics for substantially and continuously bonding to themineral-containing layer. Surface roughness values are based upon ParkerPrint Surf (μm) and Bendtsen (mls/min) per TAPPI T-479 (moderatepressure), TAPPI T-538, and TAPPI 555 (print-surf method). Tearresistance per TAPPI T-414 standards are expressed in millinewtons (mN).Surface brightness is expressed per TAPPI 452. Burst strength isexpressed per TAPPI 403 standards. Bursting strength is reported asburst ratio=bursting strength (lbs/in²/basis weight (lbs/ream). Internalbond strength or interlayer strength of the fiber-containing layer is animportant characteristic as represented by TAPPI T-403 and T-569.Preferred fiber-containing layer internal strengths are, but are notlimited to, from about 125 J/m2 to about 1150 J/m². Further,fiber-containing layer Z-direction tensile strength per TAPPI T-541testing standard is from about 45-50 Nm/g to about 950 Nm/g. Finally,preferred, but non-limiting, fiber containing layer air resistance perTAPPI 547 is from about 0 to about 1500 mls/min, as represented by theBendsten method.

TABLE 8 Fiber-Containing Layer Characteristics Fiber Weight TearResistance Surface Burst Strength (lbs/3 msf) g/m² (Mn) Roughness (kPa)40-75  60-110 400-700  2.0-5.5 μm 140-300  >75 110-130 650-700  2.0-3.5μm 175-400 >115 180-190 1400-1900 100-2500 mls/min 175-475 >130 205-2151600-2200 100-2500 mls/min 250-675 >200 315-330 1900-3200 100-2500mls/min 500-950 >300 460-195  500-4000 100-2500 mls/min  700-1850

Table 9, below, displays finished composite board barrier performanceranges, but is not limited to, that of a composite structure having fromabout 20% to about 70% mineral-containing layer bonded to at least oneside of a fiber-containing layer. The mineral-containing layer can beeither a dispersed monolayer or non-interspersed coextrusion, forexample.

TABLE 9 Barrier Values of Formed Composite Structure TAPPI Test MethodTAPPI T441 T464 TAPPI T410 TAPPI T559 WVTR in Cobb Water TropicalMineral layer Test Name Absorption Conditions Wgt Grease Resistanceg/100 lb/1000 units g/m² g/m² in² g/m² ft² 3M Test Kit # 2 30 Sampleminute minute Coated Uncoated # Fiber Layer Cobb Cobb Side Side 1Recycled .28 0.22 — 23.4 1.51 *12  **1-   Fiber mil caliper 2 Virgin .200.40 0.00 15.2 0.98 32.3 4.12 12 1- Fiber mil caliper 3 Recycled .200.00 — 18.6 1.20 3.45 12 1- Fiber mil caliper 4 85-100% .20 0.10 0.0513.9 0.89 18.25 3.55 12 1- Recycled mil Fiber caliper 5 Virgin- .30 — —7.58 0.49 12 1- TMP mil content caliper 6 Clay coated .18 — 0.45 7.130.46 7.5 12 1- 1 side- mil bleached caliper 7 Fiber 2- .18 0.00 — 9.310.6 6.44 12 1- side mil bleached caliper 8 Fiber 1 .18 0.50 0.11 37.72.43 11.33 12 1- side, mil bleached caliper 9 Virgin .16 0.05 0.11 15.00.97 3.94 12 1- Craft-clay mil coated caliper 10 Virgin .14 0.00 0.1014.1 0.91 28.1 3.89 12 1- Craft-clay mil coated thick 11 Clay .18 0.000.05 13.0 0.84 6.2 12   1- coated, mil unbleached caliper Kraft-100%virgin 12 Solid .18 0.00 0.00 9.49 0.61 52.2 5.5 12 1- Unbleached milSulfate caliper Note: 1 mil = 1/1000^(th) of an inch

Table 10, below, shows the barrier performance of a formed compositehaving a monolayer HDPE-PE mix with a density from about 0.925 gm/cm³ toabout 0.960 g/cm³ and containing from about 36% to about 45% mineralcontent by weight.

TABLE 10 Barrier Values of a Formed Composite Structure, Interspersed(Mono), Mineral Containing Layer WVTR in Tropical Cobb Water ConditionsMineral layer Fiber Type Absorption 100° F./90% R.H. weight Unit g/m²g/m² g/100 in² g/m² lb/1000 ft² Sample 2-min 30-min Recycled 0.2 0.116.7 1.08 24.9 5.09 Recycled 0.0 0.0 9.7 0.63 49.6 7.4 Virgin 0.0 0.111.1 0.72 32.8 6.73 Kraft Virgin 0.1 0.1 9.9 0.64 36.9 7.57 Kraft Virgin0.0 0.1 8.7 0.56 36.2 7.42 Kraft Virgin 0.0 0.2 7.8 0.50 41.0 6.46 KraftVirgin — — — — 26.1 5.35 Kraft

Table 11, below, shows projected moisture barrier performance (MVTR,WVTR) for the present embodiments, comparing a coextrudedmineral-containing layer bonded to a surface of a fiber-containinglayer, the mineral-containing layer having both a monolayer and amultilayer (coextrusion) construction. The fiber-containing layer inTable 11 lists Klabin virgin Kraft fiber. However, the data isapplicable to a range of both virgin and recycled fiber surfaces toinclude similar various weights and densities known in the art. MaximumMVTR via coextrusion is projected to be about the values in Table 11 inmineral-containing layers down to about 12 g/m² layer weight. The dataillustrates two different MVTR values. The first value is coextrusion.Coextrusion can provide superior results because of the flexibility toalter the type of polymers used per layer, density, branched or linearmolecular nature, as well as crystallinity, among others. Also, becauseof stress fracturing found in more monolayer constructions as a resultof bending, scoring, and processing, performance improvements usingcoextrusion are possible. The base layer in the coextrusion can be moredense and crystalline, for example, than the outer layer, which is moreamorphous and light density and more linear, thus not as vulnerable tostress fracture within the matrix, preventing percolation through thelayer. Other options for improving processing include additives to themineral-containing blend, which include, but are not limited to,elastomers.

TABLE 11 Barrier Attributes of Mineral-Containing Layer Bonded toFiber-Containing Layer Based for Interspersed (Monolayer) andNon-Interspersed (Coextruded) Mineral Composite Flat Samples Full CaseLayer Project Barrier Performance Table Fiber Layer - Outer layer PreScore + Bed Post Score Weight Ethylene Co-Polymer Uncoated MineralRanges WVTR-Tropical WVTR WVTR Ranges Mineral Layer Density - - - %Amorphous Box board 38-65% gm/m2 day Variation gm/m2 day Variation Range1.22-1.41 g/cm3 25%-65% 20 pt. 2+ layer 5 to 13 0.20 11 to 17 0.2 15 gsm50 gsm Klabin coex 1.22-1.36 g/cm3    25-70% 20 pt. Monolayer 8 to 220.2  14 to 25 0.2 15 gsm 50 gsm Klabin

FIG. 1 is a schematic side cross-sectional view of a multilayerrepulpable packaging composite material 20 according to the presentembodiments. The illustrated embodiment includes a mineral-containinglayer 22 having an outer or heat-sealable surface 24. FIG. 1A is adetail view of the portion of FIG. 1 indicated by the circle 1A-1A. Asshown in FIG. 1A, a plurality of mineral particles 26 are interspersedwithin a bonding agent 28, which may be a thermoplastic. With referenceto FIG. 1, the mineral-containing layer 22 may be substantially andcontinuously bonded to a first surface 30 of a fiber-containing layer32. Another mineral-containing layer 22 may be substantially andcontinuously bonded to a second surface 34 of the fiber-containing layer32, the second surface 34 being opposite the first surface 30. Withreference to FIG. 1A, the fiber-containing layer 32 includes a pluralityof fiber particles 36 interspersed within a bonding agent 38, which maybe a thermoplastic. The thermoplastic bonding agent of either or both ofthe mineral-containing layer 22 and the fiber-containing layer 32 maycomprise, for example and without limitation, polyolefin, polyester, orany other thermoplastic or polymer-containing resins.

The mineral-containing layer(s) 22 may include about 30% to about 65%minerals, and the minerals may comprise any of the minerals describedthroughout this specification and combinations thereof. Themineral-containing layer(s) 22 may be adhered to the fiber-containinglayer 32 through coextrusion, extrusion-lamination, or any othersuitable method or process. Extrusion-lamination may comprise aseparately applied adhesive between the mineral- and fiber-containinglayers. The composite material 20 illustrated in FIG. 1 mayadvantageously be used as a single or multiple corrugate liner(s) ormedium(s) within a single layered or multilayered conjugated structure.

FIG. 2 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material 40 according to the presentembodiments. The illustrated embodiment includes a mineral-containinglayer 22 substantially and continuously bonded to the first surface 30of a fiber-containing layer 32. In contrast to the embodiment of FIG. 1,in the embodiment of FIG. 2 the second surface 34 of thefiber-containing layer 32 is not bonded to a mineral-containing layer22.

FIG. 3 is a schematic side cross-sectional view of a repulpable mineralcontaining material according to the present embodiments. Theillustrated embodiment includes a mineral-containing layer 22 havingboth the first and second surfaces 30, 34 uncovered by amineral-containing layer 22.

FIG. 4 is a schematic detail view of a pellet 42 of a mineral-containingresin with mineral particles interspersed within a bonding agent,according to the present embodiments. Pellets such as that illustratedin FIG. 4 may be used in an extrusion process to adhere themineral-containing layer 22 and the fiber-containing layer 32 to oneanother. With reference to FIG. 4, the mineral particles 26 areinterspersed within the bonding agent 28 within the pellet 42.

FIG. 5 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments. The illustrated embodiment includes a firstmineral-containing layer 22 substantially and continuously bonded to thefirst surface 30 of a fiber-containing layer 32. A secondmineral-containing layer 44 is substantially and continuously bonded tothe second surface 34 of the fiber-containing layer 32. The secondmineral-containing layer 44 comprises three layers or plies of the firstmineral containing layer 22. The first and second mineral-containinglayers 22, 44 may be secured to the fiber-containing layer 32 throughany of the processes described herein, such as coextrusion,extrusion-lamination, etc., or through any other process. The plies 22of the second mineral containing layer 44 may be secured to one anotherthrough any of the processes described herein, such as coextrusion,extrusion-lamination, etc., or through any other process. One or more ofthe plies 22 may comprise a mineral content and/or a bonding agent thatis different from the mineral content and/or the bonding agent ofanother one or more of the plies 22. Further, the illustrated embodimentin which the second mineral-containing layer 44 comprises three layersor plies 22 is only one example. In other embodiments the secondmineral-containing layer 44 may have any number of layers or plies 22,such as two layers or plies, four layers or plies, five layers or plies,etc. In yet further embodiments, the fiber-containing layer 32 may havea multilayer mineral-containing layer 44 adhered to both the first andsecond surfaces 30, 32.

FIG. 6 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material 46 according to the presentembodiments. The material 46 of FIG. 6 includes multiple layers of anyof the material layers described herein, such as a first dual layer 48and a second dual layer 50 with a corrugated layer 52 there between.

The composite materials illustrated in the foregoing figures anddescribed above are well-suited for use as packaging materials, such asfor packages for containing one or more products. For example, andwithout limitation, such packages may comprise folding cartons and/orboxes. The package material has high performance heat sealcharacteristics, elevated barrier performance, is repulpable, andprovides excellent cosmetics and favorable economics. The presentcomposite materials can also be used as components, or layers, ofmultilayer packaging structures, such as corrugated boxes, and/or beused as a single-layer or multilayer corrugated liner or medium.

EXAMPLE 1

To form a repulpable composite, a 38.5% by weight mineralized HPDE-PEresin containing additives was compounded using wet ground and coatedfor dispersion finely ground within a range of about approximately 5-14micron mean particle sized limestone-originating CaCO₃ particles withincremental crystalline silica content within a range of from about 0.2%to about 3.5%. The specific heat of the ground CaCO₃ particles was fromabout 0.19 to about 0.31 kcal/kg·° C. The HDPE had a density within arange of about 0.939 to about 0.957 g/cm³ and the PE had a density offrom about 0.916 g/cm³ to about 0.932 g/cm3. The HDPE-PE bonding agenthad a melt flow index of 14 g/10 minutes. The finished and pelletizedmineralized compound had an approximate density within a range of aboutof 0.125 to about 1.41 g/cm³. The compound was coextruded using themineralized HDPE-PE composite layer as a base layer applied at 22 g/m²coating thickness contacting the uncoated side of 320 g/m2 weight Klabinvirgin paper surface having a TAPI T-441 Sheffield Smoothness of 74, a7.5% moisture content, and a TAPPI T 556 MD-CD Taber Stiffness of 39.9and 17.4, respectively. The minor layer, or top facing, outer, polymerbonding agent mineral-containing layer of the coextrusion was about 8g/m² weight having a mineral content from about 4% to about 65%, thebase layer being predominately crystalline using the top layer toprovide additional moisture barrier at box bend, scoring, and foldingjoints. The extrusion processing condition melt temperature for the baselayer was within a range of approximately 560° F. to 610° F. with barreltemperatures from zone one to zone six from about 405° F. to 600° F.Base layer die temperature zones were approximately 575° F. to 600° F.The extruder die gap setting was within the range of 0.025″-0.046″.Unfilled Westlake® brand top neat PE mineral-containing layer processingwas consistent with neat LDPE. The extruder air gap was approximately4″-10″, providing sufficient base layer oxidation and excellent adhesionuse gas pre-heat, but without ozone or primer layers. The extrusion linespeeds were within the range of 150-600 meters per minute across a fiberweb with within 50″-118″ range. Post corona treatment was used. Rollstock was in-process quality control checked for adhesion using “tape”testing and saturated for pin holing. Coat weight testing was doneconsistently using lab instrumentation. Finished and coated roll stockwas rewound and sent for converting. Successful converting and packagingarticle forming, e.g. folding cartons/boxes, were done up to eightmonths post-extrusion coating. Using room temperature adhesives duringconverting, the roll stock was run on high speed detergent boxproduction lines at speeds from about 100 to 500 cartons per minute. Theenclosed detergent, being sensitive to moisture exposure, was shipped intropical moisture conditions. Glue seams and small, medium, and largecarton sizes were successfully formed having sufficient fiber tear,meeting standards with both room temperature and hot melt adhesives,including the manufacturer's seam. Moisture barrier testing wascompleted for large size sampling sizes, which included full convertedand formed case samples having MVTR performance of 13.91 g/m2/24 hourswith a minimum of 13.03 g/m²/24 hours, with a standard deviation of0.86. These results compared to 40 g/m² inline primed and then appliedaqueous PVDC coatings on the same Klabin board having an average MVTR of18.92 g/m²/24 hrs with a minimum of 16.83 g/m²/24 hours, a maximum of20.89 g/m²/24 hrs, with a standard deviation of 2.00, and also comparedto 20 micron thick BOPP primed and roll-to-roll laminated on the sameKlabin board having an average MVTR of 15.03 g/m²/24 hrs with a minimumof 13.20 g/m²/24 hrs, a maximum of 16.6 g/m²/24 hrs, with a standarddeviation of 1.41.

EXAMPLE 2

To form a repulpable and recyclable composite, a 43.5% by weightmineralized PE resin containing additives was compounded using wetground and coated with fatty acid containing materials for dispersionand finely ground approximately 4-12 micron mean particle sizedlimestone-originating CaCO₃ particles with incremental crystallinesilica content of less than from about 0.2% to about 5%. The resin blendalso had 5% by weight titanium dioxide (TiO₂) for a total mineralcontent of from about 48.5% by weight. The specific heat of the groundCaCO₃ particles was 0.21 kcal/kg·° C. The PE had a density of 0.919g/cm³ to about 93.1 g/cm³. The PE bonding agent had a melt flow index of16 g/10 minutes. The finished and pelletized mineralized compound had anapproximate density of 1.38 g/cm³. The compound was then extruded usingthe mineralized PE and TiO₂ composite layer as a mono layer applied at32 lbs/3 msf coating weight contacting the uncoated side of Rock TennAngelCote® approximately 100% recycled fiberboard with a nominal basisweight of 78 lbs/msf, with the paper surface having a TAPPI T-441Sheffield Smoothness of approximately 68-72, a 5% to 7.5% moisturecontent, and a TAPPI T 556 MD-CD Taber Stiffness g-cm of 320 and 105,respectively. The extrusion processing condition melt temperature wasapproximately 585° F. with barrel temperatures from zone one to zone sixfrom about 400° F. to about 585° F. Die temperature zones wereapproximately 575° F. to 585° F. The extruder die gap setting was withinthe range of 0.025″-0.030″. The extruder air gap was approximately6″-10″, providing excellent extrudate to fiber adhesion without a gaspre-heat, ozone, or primer layers. Extrusion line speeds were within therange of 150-1400 feet per minute across a 80″-118″ web width. Postcorona treatment was used. Roll stock was in-process quality controlchecked for adhesion using “tape” testing and saturated for visual pinholing. Post production coat weight testing was done consistently usinglab instrumentation. Finished and coated roll stock was rewound and sentfor converting. Successful converting and packaging forming was done upto three months postextrusion coating. During converting, the roll stockwas run for use in high barrier MVR requirement frozen seafood boxproduction lines at speeds up to 250 boxes per minute. The finishedcomposite material was formed, bent, scored, and machined at standardproduction rates. The mineral-containing surface layer was efficientlyoffset printed using standard industry inks and aqueous press coatings.The mineral coating layer was highly opaque and improved the brightnessof the base paper surface from about 59 bright to about 76 bright. Themineral layer had a resident dyne level range of 44-48 as measuredduring post-production testing. Moisture barrier testing was completedfor large size sampling sizes, which included full converted and formedcase samples having MVTR performance of 12 to 16 g/m²/24 hrs@ 100%humidity in tropical conditions with mineral composite layer coatweights from 12 lbs/3 msfto 16 lbs/3 msf.

EXAMPLE 3

Example 3 illustrates three different finished repulpable compositescontaining bleached virgin board SBS paper within a caliper range fromabout 0.014″ to about 0.028″ having a mineral-containing layerextrusion-coated to the fiber-containing layer. These composites wereanalyzed for ash content with Tappi standard T21 1, and forrepulpability using an in-house procedure developed by the GeorgiaInstitute of Technology. Results indicated that ash content varied fromabout 2.21% up to about 21.44%. Screen yield and overall recovery seemto depend at least in part on ash content of the starting paper. A 40%by weight mineralized PE resin and a 47% by weight mineralized PE resin,both containing additives, were compounded using wet ground and coatedfor dispersion finely ground approximately 5.0 to 13.0 micron meanparticle sized limestone-originating CaC03 particles with incrementalcrystalline silica content of less that about 5% by weight. The specificheat of the ground CaCO₃ particles was 0.21 kcal/kg·° C. The PE had adensity from about 0.919 g/cm³ to about 93.2 g/cm³. The PE bonding agenthad a melt flow index of 16 g/10 minutes. The finished and pelletizedmineralized compound had an approximate density from about 1.34 g/cm³ toabout 1.41 g/cm³. The compound was then extruded as a mono layersubstantially and continuously applied on the fiber-containing layer atfrom about 7.5 lbs/3 msf to about 16 lbs/3 msf layer weight contactingthe uncoated side of International Paper Fortress SBS and ClearwaterPaper Candesce SBS having approximately 89% to approximately 100%bleached virgin fiberboard with nominal basis weight from about 182 lbsto about 233 lbs, with the paper surface having a TAPPI T-441 SheffieldSmoothness of approximately 68-72, a 5% to 7.5% moisture content, and aTAPPI T 556 MD-CD Taber Stiffness g-cm above 375 and 105, respectively.The extrusion processing condition melt temperature was from about 565°F. to about 610° F., with barrel temperatures from zone one to zone sixfrom about 400° F. to about 605° F. The die temperature zones wereapproximately 575° F. to 610° F. The extruder die gap setting was withinthe range of about 0.020″-0.040″. The extruder air gap was approximately4″-16″, providing excellent extrudate to fiber adhesion without a gaspre-heat, ozone, or primer layers. The extrusion line speeds were withinthe range of 150-1600 feet per minute across a 55″-118″ web width. Postcorona treatment was used. Roll stock was in-process quality controlchecked for adhesion using “tape” testing and saturated for visual pinholing. Post production coat weight testing was done consistently usinglab instrumentation. Finished and coated roll stock was rewound and sentfor converting. Successful converting and packaging forming was done upto three months postextrusion coating. During converting, the roll stockwas run for use in high barrier MVR requirement frozen seafood boxproduction lines at speeds up to 250-500 boxes per minute, and cupstockas well as ice cream packaging material converted from about 150 toabout 600 formed units per minute. The finished composite material wasformed, bent, scored, and machined at standard production rates. Themineral-containing surface layer was efficiently offset printed usingstandard industry inks and aqueous press coatings. The mineral coatinglayer was highly opaque and maintained the fiber layer brightness of thebase paper surface from about 80 to about 90 bright. The mineral layerhad a post corona treatment resident dyne level range of 42-56 asmeasured during post-production testing. Moisture barrier testing wascompleted for large size sampling sizes, which included full convertedand formed case samples having MVTR performance of about 8 g/m²/24 hrsto about 16 g/m²/24 hrs @ 100% humidity in tropical conditions withmineral composite layer coat weights from about 7.5 lbs/3 ms to about 16lbs/3 msf. Packages were closed and sealed using standard heat sealprocedures found on cup forming and folding carton production lines.

EXAMPLE 4 Repulpability Experiment

1. Ash Content

Ash content was measured following Tappi standard T413. The time atmaximum temperature was extended to eight hours to ensure complete ash.

TABLE 12 Ash/Solids Content for Six Paper Samples Ash/Solids ContentSample Dish, g Sample Wt., g Solids, % Ash Content, % 1# 27.7401 1.144695.83 21.41 Duplicate 15.8099 1.1136 96.20 21.46 Average 96.02 21.44 2#18.8742 1.0837 96.16 5.41 Duplicate 16.1962 0.9697 96.11 6.45 Average96.14 5.93 3# 15.7174 1.0131 95.92 2.17 Duplicate 16.5933 1.0285 95.732.26 Average 95.83 2.21 4# 17.9733 0.9974 96.09 9.31 Duplicate 18.48391.0778 95.75 9.32 Average 95.92 9.32 5# 16.3182 1.0548 95.92 4.11Duplicate 18.3800 1.2260 96.28 3.83 Average 96.10 3.97 6# 28.1106 1.377294.88 2.80 Duplicate 27.5611 1.5707 95.24 2.76 Average 95.06 2.78

The above results indicate that the ash content of sample 1# is 21.44%,the highest among the six samples, whereas that of sample 3# is only2.21%. It is contemplated that the values shown in Table 12 above mayvary by about ±50%.

2. Repulpability

Around 25 g of oven dried paper samples were torn into 1″×1″ pieces andweighted into a preheated (around 52° C.) Waring blender, which wasequipped with a special blade to reduce fiber cutting. After 1,500 ml ofhot (around 52° C.) water was added, the paper was disintegrated on lowspeed (15,000 rpm) for 4 minutes. The content was then transferredquantitatively into a British disintegrator using 500 ml hot water asrinsing liquor, so that the pulp slurry had a temperature around 52° C.The pulp suspension was then de-flaked for 5 minutes with a Britishdisintegrator at 3,000 rpm. The disintegrated pulp was screened by usinga Valley flat screen with 0.01″ slot openings for 20 minutes. During thescreening, a water head over the screen was maintained at 3″ and waterflow was kept constant. Accepts and rejects were collected and were usedto calculate the screen yield (accepts/starting paper*100) and overallrecovery ((accepts+rejects)/starting paper*100). Images of the acceptsand rejects were taken to examine the fibers and flakes. After fullcompletion of the repulpability cycle, the entire procedure wascompleted without using an acid wash to clean the flat screen during thetest or dismantling the pressure screens to clean them before completingthe test. Also, there was no visible deposition on any part or thedisintegrator during the test.

TABLE 13 Repulpability Data of the Paper Samples Screen Overall SampleStart Pulp, g Accepts, g Rejects, g Yield, % Recovery, % #2 26.44820.511 1.754 77.55 84.18 #3 25.203 19.421 1.963 77.06 84.85 #5 26.23520.700 2.044 78.90 86.69

The samples were disintegrated for 70,000 revolutions. It iscontemplated that the values shown in Table 13 above may vary by about±50%.

3. Determination of Fibers, Plastics, and Ash Compositions—DeterminedAsh Content of the Fraction Following the Procedure Stated in 1 (above)

Around 0.2 g was weighted into a 50 plastic vial. After 1.8 ml of 72%sulfuric acid was added, the content was mixed thoroughly and the samplemass turned to a paste. The vial was then set in a 30° C. heating blockfor 1 hour, and the content was stirred periodically. By the end of theheating treatment, water was added to the vial until a total of 50 mlvolume was reached. The vial was capped and set in a 121° C. autoclavefor two hours. This would completely hydrolyze the carbohydratecomponents and solubilize the acid soluble inorganics. By the end ofhydrolysis, the acid insoluble substances were collected over a tarredglass filter, which was preheated at 550° C. overnight. The collectedsubstances were plastics plus acid insoluble inorganics (ash), which wasdetermined by the procedure stated under heading 1 above. Thus, thefiber content was calculated from the weight difference of startingmaterials and substances after hydrolysis minus the acid solubleinorganics. This portion of inorganics was determined from the ashcontent stated under heading 3 above, minus acid insoluble inorganics.The plastics were the weight difference of acid insoluble substancesminus acid insoluble inorganics.

Validation—In validation run, 1.5 g starting materials was firsthydrolyzed with 15 ml of 72% sulfuric acid at room temperature for 1hour followed by a 3% sulfuric acid hydrolysis for 4 hours at boilingtemperature.

4. Stickies Analysis

Around 0.3 g materials were hydrolyzed following the procedure statedunder heading 3 above. The hydrolyzed content was filtered through blackfiltering paper (15 cm diameter). The retained white residues werethoroughly washed with water until neutral. When the filter paper wasdry, the residues on the black filtering paper were scanned with a HPscanner. A known dimension shape was placed in the scanner as areference. The image thus acquired was input to Image-J software. Setthreshold at 125/255 and scale based on the insert reference. Theparticles were analyzed and the output was input into MS Excel forfurther calculations. The stickies content was expressed as specifiedstickies area, which was defined as total stickies area in mm² /weightof starting materials in g.

5. Fate of Rosin Acids

Proper amount of mass from each fraction was weighted into 15 ml vials.After 10 ml DCM and 3 drops of 2 M HCl were added, the vial was firmlycapped with Teflon-lined caps, and shaken for 3 minutes. The vial wasset in room temperature overnight. 1 ml extract was filtered through alayer of sodium sulfate, and 100 μl clear filtrate was measured into a 1ml GC vial. After the content was dried under a stream of nitrogen, theresidues were derivatized with MSTFA (N-Methyl-N-(trimethylsilyl)trifluoroacetamide) at 50° C. for 30 minutes with periodic shaking. 1 μlderivatized mixture was injected into the GC/MS for analysis. The GC wasequipped with 60 meter SPB DB-5 fused silica capillary column and heliumwas used as carrying gas. GC operation conditions were set as follows:initial temperature 120° C., initial time 5 min., rate 15° C./min.,final temperature 315° C., and final time 30 minutes, inject porttemperature 250° C. The components were analyzed using an HP 5975C massdetector in EI mode. The operation parameters were properly set torealize maximum detection limit. Identification of individual compoundsbased on the commercial mass spectra libraries and inhouse libraries.Peak area was used to anticipate the total mass of rosin acids.

6. Starch Detection

Around 0.2 g materials were weighted into a 10 ml vial. After 5 ml waterwas added, the vial was capped and placed in a 105° C. oven overnight.Around 2 ml water extract was transferred to a test tube and added with2 drops of 0.1 M iodine solution. If the solution inside the test tubeturned to blue, it indicated that starch was present.

Results

1. Repulpability

Coated paper board and product are repulped and recovered in threefractions: accepts, rejects, and wash-out. The oven dry weight of eachfraction, along with the accepts yield and overall yield, are listed inTable 14, below.

TABLE 14 Repulpability Data of the Paper Samples Repulpability StartAccepts Overall pulp, Accepts, Rejects, Washout, Yield, Yield, g g g g %% CS-1 26.616 22.388 2.255 1.711 84.12 99.01 IP Mix 26.170 20.573 1.3763.770 78.61 98.28 CLWR_2 25.257 20.123 1.056 3.930 79.67 99.42 CLWR_8.125.550 20.572 0.919 3.941 80.51 99.53

Results indicated that the accepts yield for all studied samples isclose to 80%.

Sample CS-1 had the highest accepts yield and the least amount ofwash-out. This result may be due to the uncoating feature of the basedpaper sheet. For all the samples, the overall yield almost reaches 100%,indicating excellent recovery of the starting materials in the threefractions. All the accepts had particles of impurities in various sizes.Accepts of some samples also contain fragments of plastics that may havebeen broken down from the plastic coating. Judged from the referenceruler, the size of those particles is less than 1 mm. The rejects alsocontain small quantities of fibers. During the entire procedure, wascompleted without the use of acid wash to clean the flat screens in therepulpability tests or dismantling the pressure screens to clean thembefore finishing the recyclability test. Further, there was no visibledeposition on any part of the disintegrator during the repulpabilitytest or anticipated in a recyclability test. It is contemplated that thevalues shown in Table 14 above may vary by about ±50%.

2. Compositions of the Three Fractions

Compositions of the fractions are divided into three categories: fibers,plastics and inorganics which may come from the fillers in the basepaper and the mineral coatings in the coating layers. Through the acidhydrolysis-ash operations, the fibers, plastics and inorganics can bedistinguished and quantified. This is based on the fact that fibers arecomposed of carbohydrates and they are readily hydrolyzed in sulfuricacid solution under elevated temperature. Plastics, however, aregenerally resistant toward such hydrolysis and will be recovered asinsoluble substances. In the ashing process, both fibers and plasticswill be burnt out. Inorganics survive this process and are recovered asash.

Table 15, below, lists the experimental results indicating thepercentage of each fraction in each sample.

TABLE 15 Percent Compositions of the Three Fractions Accepts RejectsWash-out Sample Ash Fibers Plastics Ash Fibers Plastics Ash FibersPlastics Ash CS-1 0.24 98.92 0.74 0.40 3.56 96.44 0.04 82.44 1.47 17.78IP Mix 8.18 92.18 3.21 4.75 1.05 89.28 9.22 68.43 2.56 29.01 CLWR_210.33 94.43 1.04 4.53 5.05 57.43 37.52 63.07 2.21 34.72 (94.17) (1.30)CLWR_8.1 8.43 94.42 1.00 4.58 10.59 54.87 34.54 61.82 2.79 35.39 (94.11)(1.31)

Note: Data in parentheses are validation runs. Plastics columns canrepresent either mineralized layer fragments or separated plasticmaterials or both. It is contemplated that the values shown in Table 15above may vary by about ±50%.

In order to obtain reliable results, analysis to accepts of sampleCLWR-2 and CL WR-8 was performed in triplet runs: a duplicate run toproduce the average result, and a third run in large sample size toserve as validation. As indicated, the majority of the accepts isfibers, accounting for over 92% of the mass. Ash and plastics are minorcomponents existing probably in the forms of small particles. Comparingto sample CS-1, all the accepts from other three samples contains higheramounts of inorganics. As to the plastics components, IP Mix hassubstantial high quantity than CS-1, whereas those among CS-1, CLWR-2and CLWR-8.1 are comparable. Plastics are the dominant components in therejects fraction, especially in sample CS-1. Sample IP Mix, CL WR-2 andCL WR-8.1 have increasingly amounts of inorganics in the rejects. It isnot known if these inorganics are closely packed inside the plastics orpresented as separated particles. In the washout, the fibers are themajor components, especially in sample CS-1 and IP MIX. Sample CL WR-2and CL WR-8.1 have increasingly amounts of inorganics, probablypresented as colloid particles in the washing liquor.

3. Stickies Analysis

Impurities in the accepts are the major concern m the recycled pulpfibers. Although composition analysis in section 2 provides informationregarding these impurities, a visualized analysis can provide moresubtle features of the impurities. Stickies analysis (some of theparticles could also be referred to as “dirties”) is thus performed toreveal the particle content and their size distribution.

TABLE 16 Stickies Analysis Results CLWR-2 CLWR-8.1 Fibers RejectsWashout Fibers Rejects Washout Stickies, 108 n/a n/a 123 n/a n/a mm²/gRosin +++ + +++ +++ + +++ Starch + Not detected + + Not detected +

Table 16 stickie count is represented as a number of stickies containedin the accepts sampling prior to any further processing. Therefore, the3 gram hand sheets subsequently made from the accepts fibers contained100% of the stickies and other miscellaneous particles in the acceptsimmediately after pulping but before further cleansing or processingsuch as cleaning, flotation, etc. The hand sheets are pressed and driedat 350° F. and 500 psi on a Carver press for 5 minutes and tested forperformance consistent with TAPPI T 537, TAPPI T277, TAPPI T 220, TAPPI815, TAPPI T 826, TAPPI T 403, TAPPI T 831 and TAPPI T563. It iscontemplated that the values shown in Table 16 above may vary by about±50%.

Result shown in FIG. 7 indicate that contents of stickies in both CLWR-2and CLWR-8.1 are comparable. Particle size distribution plots indicatethat all the stickies have a size less than 0.4 mm. All particles havingan area less than 0.05 mm² are dominant, with approximately 80% or moreof the particles 0.0015 mm² or less. This result, however, is highly inline with what have been observed the accepts for each sampling. Sinceno further processing e.g. cleaning, reverse cleaning, flotation, highdensity cleaning, sidewall washing, peroxide dispersion, sodiumhydrosulfite bleaching, hydrosieve washing, or post flotation atspecified pH levels, etc., of the accepts occurred, 100% of the stickiesor diliies residing in the unprocessed accepts passed directly throughto the handsheets. Upon completion of the handsheets, no substantial orimportant visual or cosmetic difference from that of the virgin controlboard samples were seen. This exceptional cosmetic result is primarily afactor driven by the very small overall particle size and the white,opaque, color which closely matches the bleached board SBS fibers foundin the handsheets and control samples. Further, 100% of the particlesare less than or equal to 0.4 mm² and therefore would not be consideredlarge enough for cosmetic considerations. It is expected that themineralized board testing samples CS-1, IP MIX, CL WR 8.1 CL W 2 and thehandsheets would be considered fully recyclable fibers based onstructural, cosmetic, and other considerations including processabilitywithin about pH 6 to 8±0.5 pH levels, fiber processing temperaturelevels from about 110° F. to about 135° F., pulper consistency fromabout 1.2 to 30%, pulping time from about 10 minutes to about 40minutes, fiber on fiber yield from about 60% to about 95% and hand sheetdrying temperatures in the range of about 240° F. to about 290° F., withfinished sheet moisture levels from about 5% to 9%, recyclabilitytesting methods in accordance with testing standards established byTAPPI T220, T815, T826, T403, T83 1, T537, T277, T563.

4. Fate of Rosin Acids

Rosin is a collective name given to a group of chemicals includingabietic acid, pimaric acid, isopimirc acid, palustric acid,dehydroabietic acid, etc. The rosin used in the paper making process canalso be oxidized into different forms. Nonetheless, the acids arereadily extracted by using DCM in acidic medium, and can be easilyseparated by using a neutral GC capillary column.

Results of GC/MS analysis to the three fractions from sample CL WR-2 andCL WR-8.1 are shown in FIG. 7. FIG. 8 illustrates a typical total ionspectrum of the DCM extract.

As indicated, the rosin acids are separated completely by GC. Judgedfrom the peak area, the fibers fraction contains the highest amount ofrosin, following by the washout and the rejects. It is contemplated thatthe values shown in FIG. 8 may vary by about ±50%.

5. The Whereabouts of Starch

Starch's whereabouts among the three fractions is determined by iodinedetection. It is well known that starch will turn the iodine-containedsolution into blue color. Based on this phenomenon, starch is found inboth the fibers fraction and washout fraction, but not in the rejectsfraction, as indicated in Table 3.

EXAMPLE 5

By weight 40% to 60% mineralized resins were applied via extrusioncoating were to uncoated and clay coated virgin bleached boards withweights from about 57 lbs per thousand square feet (msl) to about 77 msfand were repulped to produce three fractions: the accepts, the rejectsand the wash-out. A full study including repulpability, compositions ofdifferent fractions, stickies analysis, fate of rosin acids and starchwere performed. Results indicated that the accept yield was over 78%,and an overall recovery of almost 100% was reached when the accepts, therejects and the wash-out were compiled. In general, the accepts weredominated with fibers, which accounted for over 92% of the mass.However, small amounts of plastics and inorganics (fillers and coatings)were also present. The rejects were mainly plastics, but significantamount of inorganics were also found in some samples. The wash-outcollected from the washing liquor contained significant amounts offibers and inorganics with small portion of plastics. Stickies contentin the accepts without any cleaning, screening, washing, or flotationwas determined in mm²/g and was 108 and 123 respectively for sampleCWR-2 and CWR-8.1. The stickies or non-fiber particles were quite uniquein composition and do not fit the standard industry definition as such,for example, they were not comprised of adhesives, hot melts, waxes, orinks. They were instead comprised of small dense fragmented mineralparticles with varying amounts of PE bonding agent attached, formingprimarily structures appearing to be easily dispersed as individualparticles within the accepted fibers. Other characteristics includedrelatively high surface energy and little, if any, tackiness. Theyappeared to resist deformability and appeared to have little potentialto cause problems with deposition, quality of sheet, and processefficiency. The stickies and other various particles were predominantlyopaque and white in color, with densities projected to fall within arange from about 1.10 g/cm³ to about 4.71 g/cm³. Because of the natureof the stickies, higher processing pH levels or peroxide bleaching wouldnot have the effect of increasing tackiness. The majority of thestickies can be defined as “micro-stickies” as they pmlicles sizes fellbeneath 150 microns in size and above 0.001 micron in size. Because ofthe benign nature of the stickie composition, it is expected they willhave little tendency to stick or adhere to equipment during processing.The data indicated that the rosin acids were found in almost all threefractions, but most of them associated with the accepts and thewash-out. An iodine detect technique found that the starch was in theaccepts and the wash-out, and the rejects was practically starch-free.

The composite structures described herein are well suited to be formedinto containers of various types. For example, FIG. 11 illustrates acontainer comprising a box 60. The box 60 may have many applications,such as, without limitation, retail and shipping. The box 60 may be inthe form of a cube or other parallelepiped that is sized to contain anitem for retail sale and/or shipping. The box 60 may be formed bypreparing the composite structure in the form of a pliable sheet, forexample by performing a milling step and/or other processing steps asdescribed above, cutting the structure into a desired shape, and thenfolding and/or creasing the sheet, either manually or by machine, suchas via an automated cartoning process, to form the finalthree-dimensional box shape. Abutting surfaces of the box 60 may besecured to one another using the various heat seal processes describedherein and/or other heat seal processes known in the art. In theembodiment shown in FIG. 11, the composite structure forms the walls ofthe box 60, including a bottom wall 62, one or more side walls 64, aswell as a foldover lid portion 66.

In other embodiments, the composite structures described herein may beformed into a container liner 70 for retail and/or shipping use, asshown in FIG. 12. The liner 70 may be used to line a shipping or retailcontainer 72 to cushion and/or protect a product held in the container72, as well as to provide moisture resistance and deter infiltration ofrodents and other pests. The liner 70 fornled of the composite structuremay be sufficiently flexible and pliable such that it is capable of atleast partially conforming to the shape of the container 72.

In other embodiments, the composite structures described herein may beformed into a shipping mailer 80, such as an envelope, which may be usedto ship documents and/or other items, as shown in FIG. 11. The compositestructure may be used to form a part of or even all of the mailerstructure 80, and may be fabricated by using a series of folding,creasing, and/or adhesive/heat seal steps to prepare the desired mailershape.

In other embodiments, the composite structures described herein may beformed into a display tray 90 and/or other sales displays, as shown inFIG. 12. For example, the composite structure may be cut, shaped, and/orfolded into the shape of a display tray 90 capable of holding anddisplaying products for retail sale. The composite structure can bemolded by bending and/or folding, as well as via thermo- and/orvacuum-forming to form desired parts of the display 90.

Other non-limiting examples of applications for which the presentembodiments are well suited are described in one or more of thefollowing publications, each of which is incorporated herein byreference in its entirety: U.S. Patent Application Publication Nos.2009/0047499, 2009/0047511, and 2009/0142528.

The above description presents various embodiments of the presentinvention, and the manner and process of making and using them, in suchfull, clear, concise, and exact terms as to enable any person skilled inthe art to which it pertains to make and use this invention. Thisinvention is, however, susceptible to modifications and alternateconstructions from that discussed above that are fully equivalent.Consequently, this invention is not limited to the particularembodiments disclosed. On the contrary, this invention covers allmodifications and alternate constructions coming within the spirit andscope of the invention as generally expressed by the following claims,which particularly point out and distinctly claim the subject matter ofthe invention.

What is claimed is:
 1. A method of recycling a composite materialcomprising: obtaining a composite material comprising a fiber layer anda barrier layer that is coupled to the fiber layer, wherein the barrierlayer comprises a mineral containing layer having a mineral content of15% to 70%; pulping the composite material to produce released fibersand mineral containing layer fragments having an area of less than 0.1mm² and a density ranging from 1.01 g/cm³ to 4.25 g/cm³; and removingunwanted materials comprising at least a portion of the mineralcontaining layer fragments from the released fibers by a screeningprocess having a rejection rate of less than 25% by weight of thecomposite material, wherein screen cleanliness efficiency is greaterthan 60%.
 2. The method of claim 1, wherein the screening processcomprises applying a suspension comprising released fibers to one ormore screening plates.
 3. The method of claim 2, wherein at least one ofthe one or more screening plates are selected from the group consistingof a hole screen, a slotted screen, and a contoured screen.
 4. Themethod of claim 3, wherein the hole screen comprises one or more holescreen openings having a diameter of 0.8 mm to 1.5 mm.
 5. The method ofclaim 3, wherein the slotted screen comprises one or more slotted screenopenings having a width of 0.1 mm to 0.4 mm.
 6. The method of claim 3,wherein the contoured screen comprises one or more contoured screenopenings have a width of 0.1 mm to 0.4 mm.
 7. The method of claim 2,wherein a pressure drop across the one or more screening plates is lessthan 12 kPa of Feed-Accept pressure.
 8. The method of claim 1, furthercomprising a post-screening process step comprising centrifugal cleaningof screen accepts, wherein the screen accepts comprise at least aportion of the unwanted materials and at least a portion of the releasedfibers.
 9. The method of claim 8, wherein the centrifugal cleaning isperformed in a tapered cylinder.
 10. The method of claim 9, whereincleaned fibers comprising the released fibers separated from theunwanted materials are carried inward to an accepted stock inlet. 11.The method of claim 8, wherein the unwanted materials comprise at leasta portion of the mineral containing layer fragments, and wherein greaterthan 70% by mass of the mineral containing layer fragments of theunwanted materials are removed from the screen accepts.
 12. The methodof claim 11, wherein the mineral containing layer fragments are at leastpartially spherical and have a diameter of 0.05 μm to 150 μm.
 13. Themethod of claim 1, wherein the caliper of the composite material is0.254 mm to 0.762 mm.
 14. The method of claim 1, wherein overallrecovery of the fiber layer is greater than 70%.